The thrust in solid state technology is to provide increasing amounts of circuitry within single large scale integrated packages in order to conserve space, reduce cost and to enlarge capability and effectively in electronic systems. Coincident with the impetus to design ever increasing amounts of circuitry within large scale integrated packages is the trend to populate printed circuit boards with larger numbers of these packages of like kind, such as those used for memory arrays in computing systems. Although the increase in density both internally within the large scale integrated component package and the use of more packages per printed circuit board greatly conserves space and provides a lower cost per bit, such packaging generally increases heat generation to the extent that more costly and more complex methods of cooling printed circuit boards and their associated solid state components are generally required. Many ways have been conceived to provide heat sinks for individual circuit components. Normally these methods comprise a structure requiring some special considerations in the construction of the component which is to be cooled, such as the provision of a special tab which mates with the heat sink. To a large degree such devices are also equipped with locking mechanisms which help to maintain the intimate contact desired between the heat sink and the component. Such methods tend to increase the cost of manufacturing the circuit components and to complicate removal and replacement of the components in the event of failure. One such configuration is disclosed in U.S. Pat. No. 4,012,769, entitled "Heat Sink With Parallel Flat Faces", issued to Edwards and Pritchett.
The invention disclosed is constructed in such a manner as to provide for insertion of a thermal conductor tab which has been encapsulated into the semiconductor.
Another heat dissipating device with the same general characteristics is described in U.S. Pat. No. 4,041,524, entitled "Heat Dissipating Device For Transistor With Outwardly Extending Heat Conducting Tab", issued to Trunk and Skrobisch. In the referenced patent, the device is a wing or tab which protrudes from the casing in which the transistor is mounted over which the heat sink is mounted. A device having similar characteristics and similar requirements for special component construction is disclosed in U.S. Pat. No. 3,893,161, entitled "Frictionally Engageable Heat Sink For Solid State Devices", issued to Albert Pesak, Jr.
A removable heat sink which does not require special construction of the component is described in U.S. Pat. No. 3,572,428, entitled "Clamping Heat Sink", issued to A. T. Monaco. However, utilization of this particular device was not contemplated for cooling of a multiplicity of components densely packed in close proximity on a printed circuit board.
Devices for cooling multiple semiconductor components are described in U.S. Pat. No. 3,171,069, entitled "Diode Heat Sink Structure", issued to Koltuniak, et al., and in U.S. Pat. No. 3,727,114, entitled "Air Cooled Semiconductor Stack", issued to Oshima. The devices in the referenced patents require accurate positioning and/or stacking of the elements to be cooled and complex cooling structures not easily removed from engagement with the semiconductors after installation. The Koltuniak, et al. disclosure, for instance, comprises an integrally cast structure including an elongated longitudinal web having a plurality of bores through which a plurality of crystal-type diodes are mounted. The heat sink is further required to be mounted in an elevated manner upon posts attached to the supporting surface, after which the diodes must be installed. The Oshima disclosure discloses a structure that is used only with a pressure contact type semiconductor stack. The complexity of both of these inventions require special considerations in their fabrication which make them costly.
What is needed for present and future technology is a cooling device having characteristics which include high thermal conductivity, easy installation and removal, adaptable for engagement with and cooling of a multiplicity of densely populated solid state components, without requiring special construction of the components for mating with and locking onto the cooling device.
The present invention is directed to a device which includes all of the above named characteristics.